Safety belt pre tensioning device when the accident happened, people forward, the seat back

A safety belt pre tensioning device, when the accident happened, people forward, the seat back, if the safety belt is too loose. The result then is probably: occupant zone below slip out from the security: or, people have encountered the airbag, and the safety belt tensioning margin due to too large and not and taut, i.e. not as expected in advance a part of momentum, but the whole burden to the airbag. These two cases are likely to lead to serious occupant injury. But the problem is, the safety belt properly installed. Where the room from loose? One is due to the occupant clothes itself has a certain thickness, in addition to the safety belt device has many hidden part up room for, this room can not be eliminated, but really had an accident, also should try to eliminate the. What am I gonna do? For a device with a pre tighten the security it is responsible for the safety belt tightening moment. The process is: first by a probe is responsible for the collection of crash information, then release the electric pulse, the pulse transfer to the gas generator, detonating gas. Gas explosion expanding rapidly in the pipeline, pressure to the so-called ball chain, so that the ball in the tube to flee, drives the ratchet wheel. Ratchet wheel with uranium are connected as a whole, the safety belt is wound around the shaft. In simple terms, is the pressure of the gas ball, the ball moving pawl wheel, ratchet disk drive shaft - instantly realized the safety belt pre tighten. The whole process from perception accident to complete the safety belt pre tightening lasts only a few thousandths of a second. At the end of the pipeline is a cavity for receiving, rolling ball.

Two, the safety belt force limiters after the accident, the safety belt in the pre tightening device, has tightened. But we hope that in the stress peak after the past, safety belt tensioning force immediately reduce, in order to reduce occupant force, the special task by the safety belt force limiters to complete: in the safety belt device, one of the pre tightening device, under a safety belt winding. The shaft core is inside a steel torsion bar. When the load reaches a predetermined condition, namely start twisting rod distorted, so as to relax to a certain extent, the safety belt, the force limiting function safety belt.